Ive been storing reserves for a while. As i see it the bulk buying isn't nessecarily a bad thing when done by ordinary people, it's more of an issue when done by low key speculators. However, whoever got fooled by the idea that "there was plenty of stocks for everyone" probably doesn't understand modern economics too well. Stocks cost money, it's not interresting for companies to keep more stock than they need and in modern times thats not much. Take in mind though that most companies can increase production above their normal utilisation and that they typically would do so if their stocks started to sell faster. So, hoarders can actually be good in such a crisis in that (in a sort of way) they offer more storage capacity to an economy that can produce more and typically enough to certaintly feed the poppulation.Its kinda good to hoard in advance before many factory's need to close to contain the spread.
Hoever borders get closed, certain country's are in quarantine and lockdown, many industry's are getting offline around the world and that hurts the food processing industry. What this should do is to create shortage's of more luxurious or scarce items in the market as more non essential companies get offline and so for example food that stores long term and is packaged trough food processing can get more scarce especially if it's more a luxury food item like say chips, candy, cakes, etc. What youre far less likely to get a shortage of is things like fresh meat,dairy products, bread, rice, corn, etc. The diet is going to get more basic if this takes a fair amount of time (which i think it will) but people shouldn't starve.
Speculators however, they will look at the market, take a calculated guess what sort of goods are going to be scarce soon and still high in demand withought say much of a subtitute good. Personally i'm surprised there are still so many cigarette's on the market, i'd expect those to be bought up in volume soon to be sold on the black market, addictions need to be served and i wouldn't be surprised if some govs banned the sale of cigarette's for a few months.